What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Skybolt cowl fastener issue

agent4573

Well Known Member
Maybe I'm missing something obvious so I hope you guys can help. Getting ready to install the sky bolt receptacles and I just don't understand the design. The rivets that hold the receptacle to the flange need to be flush, so I dimpled the flanges. If I don't dimple the receptacle there's obviously a gap. If I disassemble the receptacle and dimple it, then the barrel doesn't fit without grinding. So what's the right way to do this? I can either have a gap and a weak connection to the flange, or spend the next few weeks modifying the fasteners to fix an obvious design flaw?

Edit: the receptacle is .030" thick, so countersinking isnt an option.
 

Attachments

  • PXL_20210514_023103812.jpg
    PXL_20210514_023103812.jpg
    426.2 KB · Views: 266
  • PXL_20210514_023044009.jpg
    PXL_20210514_023044009.jpg
    162.2 KB · Views: 282
Last edited:
Flanges

I did my whole Rv-10 cowl with skybolts and the skybolt flanges.

The flanges that came with the skybolt kit are .050; they get machine countersunk for the flush rivets. Nothing needs to be done to the receptacles...
 
I did my whole Rv-10 cowl with skybolts and the skybolt flanges.

The flanges that came with the skybolt kit are .050; they get machine countersunk for the flush rivets. Nothing needs to be done to the receptacles...

Looks like I get to order a complete new set of flanges then. Gonna be fun redrilling all the new flanges to match the holes I've already put in the fiberglass. There's only one picture in the instructions that show the backside of a receptacle, and you can clearly see the dimple, but the instructions do say countersink, so it's my own fault
 
Last edited:
Based on your pictures, looks like u put them in upside down. ?
I don’t recall them being that difficult.
 
Stop.
Undimple tne flanges. Then countersink them.
The flanges are 5052H32 or something similarly soft.
If you really bugger up a flange hole, just use an “oops” rivet or a shop-made “swelled shank” rivet. Of course you will have to drill up the receptacle too, but I doubt you will have any issues with the undimple and countersink. I think I did a lot of mine freehand with the piloted CS bit and swivel deburring handle.

In the future, if you think you have discovered a design flaw on something that has been successfully installed thousands of times, you might want to take a break or ask the gang first.:):)
 
Countersink the flanges, don’t dimple them. Skybolts work very well and were zero problems installing following the instructions and using their tools. My RV-3 had the hinges but my new -8 has all Skybolts. If you have ever removed/replaced the pin on the top cowl hinge in a tight engine installation, you will love Skybolts.
 
Last week sucked all around: work, plane, life, etc. I took a few days off to cool down and then made 34 spacers for the tabs I screwed up. I counter sunk the spacers to absorb the dimple and will make up the extra depth in the barrel of the retainer. There should be at least .063" of adjustment in them. I'll order new tabs for all the ones that aren't already riveted to the firewall.
 

Attachments

  • PXL_20210520_003015843.jpg
    PXL_20210520_003015843.jpg
    382.1 KB · Views: 281
Back
Top